Technical Field
The present invention relates to an image processing device, an imaging device, an image processing method, and a computer readable medium.
Background Art
Digital cameras are widely known that are provided with autofocus, in which phase difference detection methods and contrast detection methods are employed, and also what is referred to as a manual focus mode, in which a user can manually perform focus adjustment.
Digital cameras including a manual focus mode are known in which a reflex mirror is provided to enable focus adjustment while checking an imaging subject, and a method is utilized in which a split microprism screen is employed to display the phase difference visually. Utilization of a method in which contrast is checked visually is also known.
However, in digital cameras with the reflex mirror omitted that have become prevalent in recent years, since there is no reflex mirror, there is no method to check the subject-image while displaying the phase difference, and contrast detection methods have had to be relied on. However, in such cases, contrast cannot be displayed at a resolution greater than that of a display device, such as a Liquid Crystal Display (LCD), requiring adoption of methods such as enlarging a portion for display.
In recent years, therefore, a split-image is displayed within a live-view image (also referred to as a through image), so as to make the work of focusing on the imaging subject easier for an operator when in manual focus mode. Split-image used herein refers to a divided image in which a display region has been divided into plural sections, for example (such as each image divided in the up-down direction) in which displacement is imparted in the parallax generation direction (such as the left-right direction) according to focus misalignment, and is a divided image in which the displacement in the parallax generation direction disappears in an in-focus state. The operator (such a photographer) operates a manual focus ring to match the focus so that displacement of the split-image (such as each image divided in the up-down direction) is removed.
A manual focus device described in Japanese Patent Application Laid-Open (JP-A) No. 2004-40740 (hereafter referred to as Patent Document 1) includes an aperture movement means that moves an aperture opening on an imaging subject optical path along a plane perpendicular to the optical axis, and a storage means that stores two subject-images respectively imaged at two range positions to which the aperture opening is moved. A split-image combining the two subject-images is output, and a display means, also included, displays the suitability of focused state.
In the imaging device described in JP-A No. 2009-147665 (hereafter referred to as Patent Document 2), out of light rays from an imaging optical system, a first subject-image and a second subject-image formed by light rays divided by a pupil divider are each photoelectrically converted to generate a first image and a second image. The first and the second images are employed to generate a split-image, and a third subject-image formed by the light rays not divided by the pupil divider is photoelectrically converted to generate a third image. The third image is displayed on a display and the generated split-image is displayed inside the third image, and color data extracted from the third image is applied to the split-image. By applying color data extracted from the third image to the split-image in this way, excellent visibility of the split-image can be achieved.
An imaging device described in JP-A No. 2009-163220 (hereafter referred to as Patent Document 3) includes a processing means that displays on a display means a superimposed image in which a first image and a second image obtained by division using a pupil dividing means are superimposed.
A digital camera described in JP-A No. 2001-309210 (hereafter referred to as Patent Document 4) includes a display change means that detects a misalignment amount between a focus position and an imaging subject position, and changes a display content of a split-image according to the misalignment amount.
An image processing device described in WO06/030488 (hereafter referred to as Patent Document 5) includes a configuration in which, during focus operation of an optical system using a focus controller, a false image is formed with an exaggerated amount of change in resolution of an image obtained from an image pick-up device.